Electric heating unit



Oct. 18,1927. 67

' W. B. LOUTHAN ELECTRIC HEATING UNI T Filed Dec. 21 1926 attoz 1 mo;

Patented Oct. 18, 1927.

WILLIAM B. LOUTHAN, OF EAST LIVERPOOL, OHIO.

ELECTRIC HEATING I UNIT.

Application filed December 21, 1926; Serial No. 156,176.

This invention relates to electric heating units and it is an. object of the invention to provide a device of this kind embodying a resistance wire and a base or plate and wherein the wire is applied to the base or plate in a manner to bring the wire-close to the object on the base or plate to be heated.

Another'object of the invention is to pro-' vide a heating unit of this kind COIDPI'lSlIl" a grooved base or plate in whichis adapted to be positioned a resistance wire, said wire being formed with a series of foldsfall of the folds being substantially coplanar.

A further object -of the invention is to provide a unit of this 'kind comprising a base or plate having a groove in which a resistance wire is adapted to be positioned, the side walls of such-groove being undercut to facilitate the maintenance of the resistance wire in applied or working posig tion.- s

The invention consists in the details of -construction and in the combination and arrangement of the several parts of my improved electric heating unit whereby certain important advantages are attained and the device rendered simpler, less expensive and otherwise more convenient and advantageous for use, as will be hereinafter more full set forth. 4

T e novel features of my, invention will hereinafter be definitely claimed.

In order that my invention may be the better. understood, I will .now proceed to describe the same with reference to the accompanying drawing, wherein Figure 1 is a view in top lan of an electric'heating unit constructe in accordance with an embodiment of my invention, the resistance wire being shown in fragment;

Figure 2 is an en arged fra entary sectional view taken radially of the unit as illustrated in Figure 1, the resistance wire being shown transversely flexed to facilitate its application;

Figure 3 is an enlarged fragmentary sectional view taken radially of Figure 1, showingthe resistance wire in applied or working position.

As disclosed in the accompanying drawing, P denotes a plate of desired dimensions and configuration and formed of suitable electric. insulating material, such as porcelain. The upper surface of the plate P, or

base as it may be called, is herein disclosed as provided" with a plurality of concentric grooves 1 of desired width and depth with the bottom wall of each of said grooves being flattened. At thistime, however, it is to be understood that these grooves may be arranged in any manner preferred and for which reason I do'not wish to be understood aslimiting myself to concentric grooves.

The side walls a of each of the grooves 1 have their lower portions undercut, as at 2,

' the bottom or base walls of such undercut portions 2 being flush'with the of the groove 1 proper.

The resistance wire W comprised in my improved unit is formed with a plurality of transversely disposed folds 3, said folds being of such length to provide a resistance element of a width in excess of the width of the upper or outer portion of a groove 1 but snugly resting upon the bottom of such bottom wall 2 when the wire or element W is in ap lied or working position as is illustrated in Figure 3. In applying the wire or element W the same may be readily flexed transversely as indicated in Figure 2 to reduce the width of such wire or element to permit its ready application through the upper portion of the groove 1.

"When the wire or element W is within the lower portion of the groove said wire or roove and extending within the undercuts.

element will expand for close contact with a the bottom wall of the groove and this contact maintained by the marginal portions havingclose engagement with the side walls of the undercuts 2, said side walls being inclined inwardly and outwardly as is particularly illustrated injFigure 2.

It is also to be particularly noted that the folds 3 of the wire or element W are co- .planar so that when'in working or applied,

position such wire or element will have close contact with the bottom of the groove 1 in which it-is applied and also the bottoms of the undercuts 2 in which the marginalportions of such wire or element extend.

With an electric heating unit constructed.-

as herein disclosed, it will be readily noted that the resistance wire or element W111 be effectively maintained in asplied or working position yet can be rea 11y removed or applied when desired. Furthermore, it is to be particularly noted in Figures 2 and 3 that the grooves 1 are relatively shallow so that the resistance wire or element in each of such grooves will be close to the 0b]6'0t placed upon the plate or base P to be heated.

From the foregoing description it is thought to be obvious that an electric heat:

operated, and it will also be obvious that my invention is susceptible of some change and modification without departing from the principles and spirit thereof and for this reason I do not wish to be understood as limiting myself to the precise arrangement and formation of the several parts herein shown in carrying out my invention in practice except as hereinafter claimed.

I claim An electric heatin unit comprising, in combination, an insu ating member having a groove in a surface thereof, the side walls of the groove having their lower portions undercut, the side walls of said undercuts being inclined downwardly and outwardly, and a flat resistance element extending within the oove and having close contact with the ottom thereof, said element extending within the undercuts with the marginal portions of the element in engagement with the side walls of said undercuts, said element possessing sufiicient inherent resiliency to maintain the same normally flat and permitting the same to be flexed transversely for insertion within the oove.

In testimony whereof I hereunto a my signature.

WILLIAM B. LOUTHAN. 

